High-resolution, high-speed, three-dimensional optical coherence tomography at 1060 nm (3D 1060-nm OCT) images the retina and, in contrast to OCT at 800 nm, significantly increases choroidal penetration,
1–6 with less light-scattering by cataract.
2 Previously, in vivo investigation of the choroid has been possible with ultrasound and MRI, but with limited resolution.
7,8 Histology of choroidal thickness (ChT) reveals increased ChT that correlates with a higher density of vessels in the superficial choroidal layers in open-angle glaucoma,
9 atrophy of the choroidal capillary structure,
10 and neovascularization in the choriocapillaris.
11,12 Histologic studies investigated biological structures with comparable high resolution, but these were limited by preparation artifacts, shrinkage, and lack of blood supply to sustain vasculature volume.
13 Commercial OCT systems operating at 800 nm have shown choroidal penetration only in thin choroids of myopic subjects, or by imaging limited to two-dimensional (2D) horizontal scans.
14–16 The clinical value of imaging the choroid has been shown in a small sample of patients, by using OCT at 1060 nm to demonstrate ChT variation over the field of view in uveal inflammation
17 and to demonstrate an increase in vessel density at the center of choroidal neovascularization in age-related macular degeneration (ARMD).
2,18 Recent interest in the choroid led to a study in which 3D 1060-nm OCT was used to investigate ChT confined to central and four peripheral measurement locations in a healthy Japanese population.
19 However, analyzing the measurements at several image locations neglects the remaining data collected over the entire imaged field. ChT changes may occur in patients with diabetes or ARMD, and both these groups have a high incidence of cataract. With the current commercial OCT systems that work at 800 nm, cataract may reduce imaging quality or make image acquisition unsuccessful.
20 In contrast to OCT at 800 nm, light is less scattered by cataract when OCT at 1060 nm is used,
2 but it is not clear whether visualizing the ChT with a 3D 1060-nm OCT can be successful in eyes with dense cataract.